Você está perto - perto o suficiente para que as pastas possam ter sido criadas como parte do processo do Windows Update. Mas a própria atualização do Windows não descompactou os patches - ela sempre faz o download para% windir% \ SoftwareDistribution \ Download.
Essas pastas foram criadas pelo Windows Installer. Para citar este artigo do MSDN :
The ROOTDRIVE property specifies the default drive for the destination directory of the installation. If the Directory column of the Directory table indicates the root destination directory by a property name that is undefined, the installer uses the value of the ROOTDRIVE property to resolve the path to the destination directory.
If ROOTDRIVE is not set at a command line or authored into the Property table, the installer sets this property. During an administrative installation the installer sets ROOTDRIVE to the first connected network drive it finds that can be written to. If it is not an administrative installation, or if the installer can find no network drives, the installer sets ROOTDRIVE to the local drive that can be written to having the most free space.